Heating system for paper driers



March 9 1926.

A. E. BROUGHTON HEATING SYSTEM FOR PAPER DRIERS Filed March .15, 1 2sheetvsheot A l; afforuu Mamh '9 31926.

A. E. EROUGHTQN HEATING SYSTEM FOR PAPER DRIERS Filed March 15 1924 2Sweats-Sheet 2 Patented Mar. 9, 1926.

ARTHUR E. BROUGHTON, 0F MINNEAPOLIS, MINNESOTA.

HEATING SYSTEM FOR PAPER DRIERS.

Application filed March 15, 1924. I Serial No. 699,464.

To all whom it may concern:

Be it known that I, ARTHUR E. BROUGH- TON, a citizen of the UnitedStates, residing at Minneapolis, in the county of Hennepin and State ofMinnesota, have invented new and useful Improvements in Heating Systemsfor Paper Driers, of which the following is a specification.

This invention relates to improvements in steam heating systems forpaper driers, and includes novel means for removing condensate, air andother gases from the driers and for returning the condensate to aboiler.

It is my object to effect a saving of steam and at the same time to.make it possible to improve the product and increase the rate of dryingby providing apparatus in which the useful or available heat in thesteam is utilized entirely in the rolls to which it is initiallysupplied, while the temperature applied at the wet end of the machine isentirely independent of'the temperature applied at the dry end.

A further object of this invention is to provide novel and unusuallysimple and efiicient means for removing the condensate from the driersand for returning the same to a boiler. This invention also includesimproved apparatus for separating air and other gases from condensateand does away with all power driven .mechanism for removingcondensate-from the driers.

'As is well known, paper driers of the modern type supply steam at arelatively high pressure to a section or group of driers near the dryend of the machine and then withdraw at least a portion of the steam sosupplied for use at a lower pressure in a section of driers nearer thewet end of the inachine. The steam is passed successively from onesection of driers to another until it reaches the wet end, and is thencondensed and returned to the boiler or otherwise disposed of. In all ofsuch systems known to applicant, the temperature of the driers at thewet end of the machine is dependent to a certain extent at least uponthe tempera ture at the dry end. Further, to prevent searing certainkinds of paper, it is necessary to apply at a low temperature (andcorrespondingly low pressure) at the wet end of the machine, while it isimportant in order to carry out the drying as rapidly as possible toapply high temperatures and pressures nearer the dry end of the machine.\Vith this common type of machine it is not possible, withoutsacrificing a substantial amount of the available heat in the steam, toa the ry end and at. the same time to apply, as is frequently desirable,a very low temperature at the wet end. With the system of the presentinvention, however, the temperatures at the ends of the machine areentirely independent of each other, the temperatures of each section ofdriers being regulated by independent adjustment of the pressure. In thepresent system, steam at the desired pressure is transmitted to each ofthe several driers, wherein its available heat is all utilized and onlythe condensate (together with tra ped air) is withdrawn from any of thedrlers. Steam is prevented from passin from one drying roll to an otherand rom one group of driers to another.

I-Ieretofore, it has been common practice to withdraw the condensate andair from the driers by power driven means, such as a vacuum pump, fluidoperated ejector, or by reduced pressure in the'receiving header. Nosuch means are employed in the present invention, the condensate beingallowed to flow by gravity toga series of direct return traps. v

The invention will be readily understood from the following description,referring to the accompanying drawings. In the drawings, Figure 1 is adiagram of my improved system applied to .the driers of a paper machine;Fig. 2 is a diagramatic elevation partially in central, verticalsection, showing a portion of one of the driers and the apparatus forremoving air and condensate from the same; Fig. 3 is a sideelevation,partially in central, vertical section, of a suitable return trap -formy system, and Fig. 4

is a plan view of the piping and valves of said trap.

In the drawings I have used the numeral 1 to indicate-the several drierswhich. are arranged. in sections or groups and adapted ply the desiredhigh temperature at to be supplied with steam from a series of steamheaders 2, 3, 4 and 5. The driers are connected by pipes 6 with theheaders which are severally supplied with steam at difiering pressures.A high pressure steam line 7 communicates through a reducing valve 8 ofcommon type with the header 2 at the dry end of the machine, while steamat a lower pressure, preferably from the engine exhaust, is transmittedto the headers 2 and 3 by a pipe 9 having a check valve 10 ada ted toprevent flow from the pipe 7 to t e pipe 9. A branch of the pipe 9communicates with the header 4 through a pressure reducing valve 11, andsaid branch also connects with the header 5 which also may be suppliedwith steam at still lower pressures by a pipe 12 leading to the exhaustof the return traps, as hereinafter described. Valves 13 and 14 areadapted to be manipulated to open the header 5 into either the pipe 9 orpipe 12.

The pipes 6 connecting the several driers with the headers open intohollow trunnions at one end of the drying rolls, as

shown in Fig. 2, so as to supply steam to the interior thereof. Towithdraw condensate from each drier, a pipe 15 is rovided which extendsaxially through t e trunnion 16 and projects within the drier to aposition 17 near its lower periphery, whence the condensate iswithdrawn. The outer portion of the pipe 15 extends downward andcommunicates through a check valve 18 with one of the several condensateheaders 19 or 20. In order to furnish means for testing whether or notcondensate is flowing properly through the pipe 15, a valve 21 isconnected to said pipe near the lowest point therein between the checkvalve 18 and drier.

Each of the headers 19 is adapted to drain into one of a series ofreceivers 22, from which air is allowed to escape through a water trap23 and a thermostatic valve 24. Air which collects in the top of thereceiver 22 is allowed to pass through a pipe 25 into the water trap 23and then is carried to the valve 24 through a float actuated valve 26and a pipe 27. Should the receiver 22 become filled with water, anyfurther supply of water would flow into the trap 23 and cause the valve26 to close and prevent the escape of water through the air valve 24.Any steam which enters the receiver 22 is prevented from escaping by theaction of the thermostatic valve 24. To allow water, which sometimesfills the trap 23, to flow back into the receiver 22, a bypass 28 forair is placed on the tra From each of the receivers 22 water is carriedto one of a series of return traps 29 by a pipe 30, a check valve '31being provided to prevent flow from the trap toward the receiver. Thepipe 30, as shown in Figs.

3 and 4, connects with a pipe 32 which opens at 33 into the base of thetrap 29. This pipe 32 also communicates with an outlet pipe 34 leadingto a header 35 (Fig. 1), a check valve 36 being placed in the pipe 34.The trap 29 is of the tilting, direct return type operating at boilerpressure. High.

pressure steam is supplied through a pipe 37, valve 38 and pipe 39 tothe top of the trap proper and steam is exhausted from the trap throughthe pipe 39, a valve 40, a pipe 41 and a check valve 42. The trap 29 istiltably supported upon bearings 43 and is normally maintained insubstantially horizontal position by a wei ht 44 supported upon a lever45 having a fu crum 46 and pivotally connected at its end 47 to the pipe32. A stop 48 is provided for limiting the tilting movement of the trap,while levers 49 and 50 are suitably arranged and connected respectivelywith the valves 38 and 40 so as to actuate. said valves when the trap istilted.

Water is allowed to flow from the receiver 22 to the trap 29 through thepipe 30, check valve 31 and pipe '32. As the water rises in the trap-29to a predetermined level therein, the weight 44.becomes over balancedand the trap tilts in the bearings 43 to the stop 48. During the flow ofwater into the trap, the valve 40 is maintained in open position by thelever 50 and the valve 38 is closed by the lever 49. However, when thetrap is tilted to the stop 48 by'in-flowing water, the left ends of thelevers 49 and 50 (as viewed in Fig. 3) are depressed to open the steamvalve 38 and close the exhaust valve 40. High pressure steam is thusadmitted to the trap through the pipe 39 to force substantially all ofthe water out of the trap through the pipes 32 and 34 past the checkvalve 36. When substantially all of the water has been forced out, theweight 44 again returns the trap to horizontal position to thereby closethe valve 38 and open the valve 42. Pressure in the trap is thusrelieved by allowing the escape of steam through the pipe 41 whichcommunicates with the pipe 12. As soon as the pressure becomesequalized, the water again flows from the receiver 22 and the abovedescribed operation is repeated.

The several outlet pipes 34 transmit the condensate to the header 35which communicates through a check valve 51 with a high pressurereceiver 52. The pipe 35 communicates with the bottom of the receiver 52so as to allow water in the receiver to seal said pipe. High pressuresteam is supplied to the surface of the water in the receiver 52 by apipe 53. A conduit 54 is arranged to carry the condensate from thereceiver 52 to suitable boiler pumps or traps, from which backward flow'is prevented by a check valve 55 in the pipe 54. A water seal ismaintained on the open ends of the pipes 35 and 54 within the receiver52 by a float actuated valve 56 positioned in the latter pipe.

' Operation.

With certain kinds of paper, high pressures and correspondingly hightemperatures may be applied to the rolls near the dry end of themachine. Where such paper closed, the pressure in said connected header.

is to be dried, a valve 7 sure steam pipe is opened; otherwise, thevalve 7 may be closed to admit steam under engine exhaust pressureto theheader 2. The valve 11 reduces the pressure in the header 4, and wheredesirable or necessary, steam under a still lower pressure may besupplied to the wet end header 5 by opening the valve 14 and closing thevalve 13. Low pressure steam from the trap exhaust may be supplied tothe wet end driers or steam at a somewhat higher pressure may befurnished by closing the valve 14 and opening the valve 13.. Thus, aswill be readily understood, steam is supplied to the several sections orgroups of drying rolls at independently differing pressures.

Sufficient steam is supplied to each roll in the high presbeing removedfrom the rolls. As long as there is insuflicient condensate to seal theopen ends 17 of the pipes 15, the pressures in said pipes and in theheader 19 and receiver 22 remains the same as the pressure in the rolls1 of the same group. However, when sufiicient condensate collects in oneof the rolls 1 so that the end 17 of apipe 15 is drops (the check valve18 preventing any back flow from the header 19) with the re suit thatcondensate is forced into the pipe 1.5 by reason of the higher pressurein the roll. As soon as the water has been thus raised to the level ofthe axis of the roll it will flow past the valve 18 into the header 19and thence into the receiver 22. Obviously, the pressure in the rollsnearest the wet end of a group will be slightly lower than at the dryend of that group. This results in maintaining a pressurein each of theheaders 19 equalto the pressure in the rolls nearest the dry end of thecorres onding group and condensate stands above tie check valves 18 inthe pipes 15 leading to the other rolls of each group at such a heightas to compensate for the difierence in pressure in any particular rolland in the It will now be evident that condensateis withdrawn as'fast asit forms in each roll and is allowed to flow into the headers 19.

Similarly condensate is removed from the rolls 1 at the wet end of themachine but flows from the header 20 directly to the trap 29, instead ofpassing through an interpipe quickly mediate receiver. might otherwiseform pockets in the driers is removed with the condensate and deliveredto the receivers 22, whence it is allowed to escape through the trap 23and thermostatic valve 24. Water and steam is prevented from escapingwith the air by reason of the arrangement of the water 'tra 23 andthermostatio valve 24, described a ove.

-The several return traps 29 are arranged at a lower level than thereceivers 22 and headers 19 and 20, so that condensate flows freely fromthe receivers and the header 20 into the traps 29, whence it isdischarged under boiler pressure, through the pipes 34 All air and gaswhich and feeder 35 to the high pressure receiver 52. From said receiverthe water is carried. by the pipe 54 to suitable boiler feed pumps ortraps and then to the feed water place of disposal such as a feed waterheater.

ar type of return traps has been described somewhat in detail,obviously, other types of traps could be used with my invention and I donot wish to limit myself to any specific form of trap. It will also beevident that there are other suitable types of pressure reducing valvesor pressure regulators which mightbe used in place of the piston oper-While for the sake of clearness, a particu ated reducing valves 8 and 11shown diagrammatically in the drawings.

It is to be understood that where the term receiver is used in thefollowing claims that the said term indicates a header or otherreceptacle'for steam from the driers, whether of cylindrical or othershape.

Having described my invention what I claim as new and desire to protectby Letters Patent is:

1. The combinationwith a machine having a plurality 0? arranged in steamat di drying rolls roups, of means for supplying ering pressures to therolls of the several groups, and means for withdrawing condensate fromsaid rolls comprising, a header,

with said header, and check valves arranged in said pipes to preventback pressure in said pipes and to allow fluid to be drawn by ravityfrom said rolls to said header. 2. The combination with a aper makingmachine having a plurality of drying rolls, of means for-supp ying steamunder ressure to said rolls, and means for with rawin condensate fromsaid rolls comprising, a header, a series of pipes severallycommunicating atone end with said rolls and at the other end with saidheader, and check pipes severally communicating at' one end with saidrolls and at the other end aper making valves arranged in said pipes toprevent back pressure in said pipes and to allow fluid to pass from saidrolls to said header, the pressure in said header being maintainedsubstantially equal to the pressure in said rolls.

3. The combination with a paper making vmachine having a plurality ofdrying rolls arranged in groups, of means for supplying steam atdiffering pressures to the rolls of the several groups and means forwithdrawing condensate from said rolls comprising separate headers forthe several groups, pipes severally communicating at one end with saidrolls and at the other end with said headers, and check valves arrangedin said pipes to prevent back pressure in said pipes and to allow fluidto be drawn from said rolls to the headers by gravity.

4. The combination with a paper machine having a plurality of dryingrolls arranged in groups, of means for supplying steam at differingpressures to the rolls of the several groups, means for withdrawingcondensate from each of said rolls, a single receiver, means fortransmitting condensate from allof said rolls to said receiver, andmeans for preventing the flow of steam from one of said groups toanother.

5. The combination with a paper machine having a plurality of dryingrolls arranged in groups, of means for supplying steam at differingpressures to the rolls of the several groups, the heat of the steambeing utilized wholly in the rolls to which it is initially supplied, asingle receiver and means for transmitting condensate from all of saidrolls to said receiver.

6. The combination with a paper machine having a pluralit-yof dryingrolls arranged in groups, of means for supplying steam at differingpressures to the rolls of the several groups, the pressures applied inthe groups being independent one of another, means for preventing theflow of steam from one of said groups to another, a receiver for eachroup, means for transmitting fluid from sai rolls to said receivers andmeans mounted on said receiver for allowing the escape of air and gasestherefrom and for preventing the escape of steam and condensatetherefrom.

7. In a pa ermaking machine having a plurality of rying rolls, means forsupplying steam under pressure to said r0 ls, a receiver connected bypiping with said rolls whereby the pressure in the receiver ismaintained substantially equal to the pressure in the rolls, and meansadapted to permit the escape of air and gases from said receiver.

8. In a paper making machine having a plurality of drying rolls, meansfor supplying steam under ressure to said rolls, a receiver connected ypiping with said rolls whereby the pressure in the receiver ismaintained substantially equal tothe pressure in the rolls, athermostatic valve on said re ceiver adapted to permit the escape of airand gases therefrom and a water trap arranged to prevent the escape ofcondensate through said valve.

9. In a paper making machine havin a plurality of drying rolls, meansfor supp ying steam under pressure to said rolls, a receiver disposed ata lower lever than said rolls connected by iping therewith 'whereby thepressure in t e receiver is mai tained substantially equal to thepressure 'n the rolls and condensate is allowed to flow by gravity fromthe rolls to said receiver, means adapted to permit the escape of airand gases from said receiver, means for preventing the escape of steamand condensate from said receiver, a returntrap disposed beneath saidreceiver for condensate therefrom, said trap being adapted to increasethe presssure on condensate therein and an outlet pipe. from whichcondensate is allowed to flow at increased pressure from said trap.

10. In a paper making machine having a plurality of drying rolls arraned in groups, means for supplying steam at. ifferingpressures to therolls of the several groups, a

separate receiver for condensate from each or sa1d groups, pipingconnecting the rolls with the receivers whereby the pressure in the recever of each group is maintained substantlally equal to the pressure in.the rolls of the same grou a high pressure tank adapted to receive t econdensate from all of sa1d receivers, and return traps operating underan equally high pressure, severally connected to the receivers and tosaid tank and arranged to allow condensate to pass by gravit to saidtank.

11. The com ination with a machine having a plurality of drying rollsarranged in groups, of means for supplying steam at Clll'fQX'lIlgpressures to the rolls of the several groups, a separate header for thecondensate from each group, pipes severally connecting the rolls withthe headers, check valves arranged in said pipes to allow fluid to passfrom the rolls to the headers, a receiver arranged beneath each of saidheaders to receive fluid therefrom, the pressure in said rolls, headersand receivers being equalized to permit flow by gravity from the rollsto the receivers, a high pressure tank adapted to receive the condensatefrom all of said receivers and return traps and piping adapted todeliver condensate from sa1d receivers to said tank. 7

. 12. The combination with a machine having a plurality of drying rollsarranged in groups, of means for supplying steam at inde endentlydifl'ering pressures to the rolls of tie several groups, aseparateheader for the condensate from each group, pipes severally connectingthe rollswith the headers, check valves arranged in said pipes from saidreceivers, a high pressure tank to allow fluid to pass from the rolls tothe adapted to receive the condensate from all of l headers, a receiverarranged beneath each said receivers, and return traps and piping ofsaid headers to receive fluid therefrom, adapted to deliver condensatefrom said 5 the pressure in said rolls, headers and rereceivers to saidtank ceivers being equalized to permit flew by In testimony whereoffIhave hereunto gravity from the rolls to the receivers, signed my name tothis specification. means adapted to allow the escape of air ARTHUR E.BROUGHTON.

